1. Field of the Invention
The present invention relates to a multistage lock apparatus that can provide a preferred structure strength and safety.
2. Description of Related Art
A conventional multistage lock apparatus applied for a lock assembly comprises a base, a selecting disk and a disk set. The base is mounted on the lock assembly. The selecting disk is rotatably mounted on the base and has a driving rod extending through the base. The disk set is connected to the driving rod and has four disks. However, the structure strength of the conventional multistage lock apparatus is weak, and this will decrease the safety of using the conventional multistage lock apparatus. Furthermore, the conventional multistage lock apparatus has only one disk set including four disks, to unlock the multistage lock apparatus only needs four passwords, is easy and takes few time for an unauthorized person. In addition, the unauthorized person can use an electric sound collector or a stethoscope to rotate the disks in the unlock positions, and this will decrease the safety of using the conventional multistage lock apparatus. Therefore, the safety of using the conventional multistage lock apparatus needs to be improved.